C
B
72 dB
C
A
71 dB
C
B
7 dB
B
A
71 dB
C
B
72 dB
B
A
7 dB
C
A
71 dB
C
B
7 dB
B
A
71 dB
C
B
7 dB
B
A
C
B
C
B
C
A